Do the Following Questions About Filter Papar Also Bother You?
As a commonly used product in lab experiments, the filter paper is less complicated than others, but we should also know them well before use. So, do the following questions about the filter paper also bother you?
1. What roles do the qualitative and quantitative filter paper play in the lab?
The qualitative filter paper is an indispensable experimental article in laboratories, so what role does qualitative filter paper play in the experiment? It contains ash content and has little effect on the experimental effect. It is also used on the tray to prevent corrosion when weighing corrosive solids with a tray balance. The main filtering function is to filter out the mixed solid and liquid substances, so as to better achieve the solid and liquid separation.
In the process of using, because the qualitative filter paper has good moisture absorption performance, it is also used to wipe some instruments related to concentration. It has a good moisture absorption effect on the liquid on the instrument. Qualitative filter paper is suitable for filtering industrial organic suspension turbidities such as petroleum, chemical products, and industrial oil to separate solid and semi-solid impurities. For example, the supporting filter press filters a variety of organic liquids such as transformer oil, turbine oil, molten paraffin grease synthetic resin, and dioctyl sebacate. Also, there is a kind of folded qualitative filter paper, which is able to increase load capacity and flow rate.
The qualitative filter paper is used for qualitative chemical analysis and corresponding filtration separation; quantitative filter paper is used for gravimetric analysis test and corresponding analysis test in quantitative chemical analysis. To ash and weigh analysis experiments after filtration is the main usage of quantitative filter paper. After ashing, each filter paper’s ash weight is a fixed value.
2. How to distinguish between qualitative filter paper and quantitative filter paper?
The qualitative filter paper and the quantitative filter paper are both white and similar in thickness, which is difficult to distinguish. If you want to distinguish quickly, you still have to find out their differences.
Qualitative is focused on nature which is applied in corresponding filtration separation and qualitative chemical analysis and quantification is to focus on quantity ratio, which is used for gravimetric analysis test and corresponding analysis test. Generally, qualitative filter paper has large pores and small quantitative. For the quantitative filter paper, the pore size is different depending on the filtration speed. Quantitative filter paper is divided into three types: fast, medium, and slow, and its pore size is about 80-120 microns, 30-50 microns, and 1-3 microns, respectively. Of course, the distinction must be made through certain experiments, and it cannot be distinguished only by eyes.
3. In vacuum filtration and natural filtration, should I choose qualitative medium speed filter paper or qualitative fast filter paper?
The fast filter paper is selected for suction filtration, because the suction is mainly filtered by the filter cake, and the resistance is relatively large. In order to filter quickly, choose qualitative fast filter paper.
Use medium speed for natural filtration, which is slow and easy to form a filter cake, and the filtration effect is better.
4. When doing drug content determination, use qualitative or quantitative filter paper?
Quantitative filter paper should be used for filtration when determining the content of drugs. This is because qualitative analysis filter paper cannot be used for quality analysis.
During the quantitative filter paper manufacturing process, in order to remove most of the impurities, we treat the pulp with hydrochloric acid and hydrofluoric acid and wash it with distilled water, so there is very little residual ash after burning, which hardly affects the analysis results. It is suitable for precise quantitative analysis.
